New data on the stomiid teleost bathophilus nigerrimus from Mediterranean waters

In this paper new data on the scaleless dragonfish Bathophilus nigerrimus Giglioli 1882 (Stomiidae) are provided. We examined an individual found stranded on the shore of the Sicilian coast of the Strait of Messina on February 2, 2019. Additional data were retrieved by two more specimens from the same study area: from the first one, found stranded on March 1992, morphometric and meristic data were taken, and from the second, collected in good condition from a stomach of the carangid Trachurus picturatus, microincrement counts from otolith were performed. We also used data from bibliography to reconstruct the relationship between total (TL) and standard length (SL) for this species. The comparison between our data and the counts of meristic characters in previous records reveals that the number of pectoral fin rays is quite variable, due to the bad condition of some preserved specimens or damages from trawling. The analysis of the stomach content allowed to observe that a large prey (Diaphus holti; 78.89% of predator size) was present, suggesting that B. nigerrimus may base its feeding strategy on the consumption of large meals (e.g. other meso- and bathy-pelagic teleosts), to obtain an energetic advantage in deep waters. For the first time, the analysis of otolith microstructure allowed to count 231 and 168 microincrements in the examined individuals (54 and 37 mm SL, respectively). The new data reported in the present paper can be considered a step forward in the understanding of the biology and ecology of B. nigerrimus.